Kinesin-3 and dynein cooperate in long-range retrograde endosome motility along a nonuniform microtubule array.
Kinesin-3 and dynein cooperate in long-range retrograde endosome motility along a nonuniform microtubule array.
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DOI：
10.1091/mbc.e11-03-0217
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发表时间：
2011-10
影响因子：
3.3
通讯作者：
Steinberg G
中科院分区：
文献类型：
--
作者：
Schuster M;Kilaru S;Fink G;Collemare J;Roger Y;Steinberg G
我们研究了分子马达在长距离运动的早期内涵体（EE）在真菌模型系统，包含一个双极，树突状微管（MT）阵列。动力蛋白使逆行EE移动超过100 μm，然后驱动蛋白-3沿着反极MT束进一步移动超过100 μm。因此，驱动蛋白-3是逆行EE运动的主要马达。微管（MT）的极性决定了细胞内运动的马达，驱动蛋白移动到正末端，动力蛋白移动到负末端。在玉米黑粉菌的伸长细胞中，动力蛋白被认为将早期内体（EE）向隔膜（逆行）移动，而驱动蛋白-3将其运输到生长的细胞尖端（顺行）。偶尔，EE在一个方向上运行到90 μm。底层MT阵列由位于细胞两端的单极MT和位于细胞中间区域的反极束组成。用γ-微管蛋白环复合物蛋白标记的细胞质MT组织中心沿着反极MT分布，但在单极区域不存在。动力蛋白在离开细胞尖端后与EE共定位10-20 μm。失活的温度敏感的动力蛋白废除EE运动内的单极MT阵列，而长距离运动不受影响。相反，驱动蛋白-3是连续存在的，其失活停止长距离EE运动。这表明，这两个电机参与EE运动，动力蛋白运输细胞器通过单极MT阵列附近的细胞末端，和驱动蛋白-3接管在开始的内侧反极MT阵列。两个马达的合作介导整个细胞长度上的EE运动。
We studied molecular motors in long-range motility of early endosomes (EEs) in a fungal model system that contains a bipolar, dendrite-like microtubule (MT) array. Dynein moves retrograde EEs over ∼10 μm, before kinesin-3 takes over for a further ∼80 μm along antipolar MT bundles. Thus kinesin-3 is the major motor for retrograde EE motility. The polarity of microtubules (MTs) determines the motors for intracellular motility, with kinesins moving to plus ends and dynein to minus ends. In elongated cells of Ustilago maydis, dynein is thought to move early endosomes (EEs) toward the septum (retrograde), whereas kinesin-3 transports them to the growing cell tip (anterograde). Occasionally, EEs run up to 90 μm in one direction. The underlying MT array consists of unipolar MTs at both cell ends and antipolar bundles in the middle region of the cell. Cytoplasmic MT-organizing centers, labeled with a γ-tubulin ring complex protein, are distributed along the antipolar MTs but are absent from the unipolar regions. Dynein colocalizes with EEs for 10–20 μm after they have left the cell tip. Inactivation of temperature-sensitive dynein abolishes EE motility within the unipolar MT array, whereas long-range motility is not impaired. In contrast, kinesin-3 is continuously present, and its inactivation stops long-range EE motility. This indicates that both motors participate in EE motility, with dynein transporting the organelles through the unipolar MT array near the cell ends, and kinesin-3 taking over at the beginning of the medial antipolar MT array. The cooperation of both motors mediates EE movements over the length of the entire cell.